It is known to the art to incorporate enzymes into dry solid particles or granules and thereby protect the enzymes from inactivation and/or protect the environment from the enzymes. It is further known to the art to incorporate stabilizers into such granule to protect the enzymes against inactivation caused by aggressive materials in the environment.
Known prior art related to stabilization of enzymes in dry granules are:
U.S. Pat. No. 5,858,952 discloses an enzyme-containing granulated product comprising an enzyme and one or more stabilizers selected from the group consisting of reducing agents and antioxidants. U.S. Pat. No. 5,972,669 discloses methods to improve the processing and storage stability of dry enzyme preparations. To this extend an inorganic salt, e.g. MgSO4, is dissolved in an enzyme containing solution which is subsequently dried, using e.g. spray drying.
WO 91/17235 discloses granules containing enzymes and an enzyme protecting agent.
EP 206,417 discloses enzyme granular compositions comprising an enzyme core and alkaline buffer salt coating.
WO 00/01793 discloses coated enzyme granules wherein the coating comprises water soluble salt which may be slightly acidic.
GB 1,395,330 discloses use of amino acids in amylase granules.
GB 2,064,543 discloses granules containing an enzyme and sodium dihydrogen phosphate.
GB 1,415,301 discloses an enzyme granule comprising in the core alkali metal inorganic salts.
Measures to prevent the reduction of enzyme activity of enzyme-containing granulated products are disclosed by Japanese Patent Application Laid-Open (kokai) No. 62-79298, which describes an enzyme composition in which the core part containing an enzyme is coated with a protective layer containing an alkaline buffering salt of pH 7-11, and by Japanese Patent Application Laid-Open (kokai) No. 3-149298, which describes a bleaching agent containing hydrase particles, in which the enzyme nuclei are coated with a protective agent such as a water-soluble alkali metal silicate, a transition metal, or a reducing agent.
WO 99/32595 discloses enzyme granules comprising an enzyme core and a hydrated barrier material.
WO 99/32612 discloses granules comprising a protein mixed together with a salt, wherein the granules are prepared by fluid bed.